This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Patients surviving hematopoietic cell transplantation (HCT) are at an incrased risk of age-, disease-, and treatment-specific sequelae because of the intensity and nature of treatment. These sequelae can affect their neuropsychological functioning and quality of life. There exists a critical lack of information regarding neuropsychological functioning among adult patients undergoing HCT. While the majority of the small case-series report some disturbance in neurocognitive functioning among adult patients following HCT, methodological limitations, such as small sample size, have prevented reliable identification of host- and treatment-related risk factors in this population. This impairs the ability to define the magnitude of the problem with precision, as well as to study the various correlates of cognitive functioning in this rather heterogeneous population. Additionally, the cross-sectional study design used in the previous studies further limits knowledge of the timing of these impairments, as well as the natural course. Furthermore, several changes have occurred over the years with regards to the practice of HCT. The patient population considered appropriate for HCT has changed - both with regards to the age range and the disease status. The introduction of non-myeloablative transplant, as well as the use of more targeted radiotherapy could also potentially impact upon the neurocognitive functioning in this population. This study aims to evaluate patients prospectively in order to describe health-related quality of life (HRQOL) in HCT survivors and collect data on the incidence and risk factors associated with neurocognitive dysfunction and fatigue, with the aim to assess the impact of neurocognitive functioning and fatigue on HRQOL in this cohort. This study population will be extensively characterized in terms of demographic and clinical characteristics, primary diagnoses, therapeutic exposers and health status. This population of long-term transplant survivors will be followed prospectively, prior to transplant and proceeding longitudinally at various pre-determined time-points, to conduct a comprehensive assessment of neurocognitive functioning utlizing a battery of stnadardized neuropsychological assessment tests as well as self-administered questionnaires assessing neuropsychological functioning and fatigue. This study will focus on the impact of these events on the health-related quality of life (HRQOL) among these survivors. In addition, blood or buccal cells will be procured from study participants and banked prior to HCT to create a resource for future studies to examine the role of genetic susceptibility in neurocognitive impairment.